I always love it when the words "hacking" and "protest" show up in the same article.
Recently, people on Facebook were annoyed with a feature of the Facebook "groups". Basically, this feature said that if someone who had created a group left it, and there was no longer an administrator, ANYONE in the group could take the group over. You can see why this was put in place - you wouldn't want someone to abandon a group and have it just disappear, after all. However, you can also see the potential problem. Anyone can take over a group!
In protest, a group of people "hijacked" administrator privileges in around 300 groups in November, just to show that Facebook has a major issue with security.
Link to article